Change Scheduled Billing date while Bill Order creation

Hi,

I have requirement where I need to change the scheduled billing date while creating a Bill Order.

I have tried to implement a BADI : ISU_INTERVAL_CHECK for same via transaction code EL01.

There is an issue with the custom BADI created as the changing parameter of this BADI (txy_etrg) does not update the

Scheduled billing date even after modification of scheduled billing date.

Note : I have checked in debugger that changing parameter structure txy_etrg becomes an internal table outside BADI and does not contain the updated scheduled billing date.

Kindly guide how this issue can resolved.

It would be helpful if anyone can help with other BADIs or user exits which I can use to change the scheduled billing date.

Thank you in advance!